Spectrally encoded endoscopy (“SEE”) is a miniature endoscopy technology that can conduct high-definition imaging through a sub-mm diameter probe. With SEE, broadband light is diffracted by a grating at the tip of the fiber, producing a dispersed spectrum on the sample. Light returned from the sample is detected using a spectrometer; and each resolvable wavelength corresponds to reflectance from a different point on the sample. Previously, SEE procedures have been demonstrated using a 350 μm diameter probe, which produced high-quality images in two- and three-dimensions. One of the technical challenges for fabricating SEE probes has been to make a sub-mm transmission grating with a high diffraction efficiency and to precisely assemble the miniature grating with other optical components in the probe.
In International Publication WO2014/031748, a method for fabricating or otherwise providing miniature gratings for SEE probes using, e.g., “soft” lithography was described. In this exemplary method, an elastomeric stamp with a grating pattern is first fabricated by replica molding of the master grating. The miniature grating then is fabricated by replica molding of the elastomeric stamp. This approach, however, has challenges in fabricating the elastomeric stamp when the aspect ratio of the grating pattern is very high. Soft material does not provide enough stiffness to replicate the grating pattern, while hard material cannot be easily removed from the master grating due to the friction between the hard elastomeric stamp and master grating.
Thus, there is a need to improve or at least partially address the above-described deficiencies and/or issues associated with the SEE probe fabrication of SEE probes.